Changes in population structure
Since 2001 there have been changes to the UK's population structure.
In recent years there have been significant changes to the UK population pyramid. The main changes have been an increase in the number of children aged under ten years old, an increase in the number of older adults aged 45 to 55 and an increase in older people aged 90 or over.
Increase in children
This is partly due to the higher birth rates of migrants who have entered the country in recent years. In addition, migrants may come from countries where birth rates are higher. Fertility rates amongst older women in the UK has also risen slightly. In 2021, the largest increase in fertility rates was among those aged 35 to 39 years.
Increase in older adults
There was an increase in net migration into the UK after 2004 when 10 new Eastern European countries joined the EU and gained the right to live and work in the UK. These young adults left countries such as Poland to seek work. Many of these migrants have permanently settled in the UK and aged to become older adults.
Increase in over 80s
Along with the factors associated with the growth of an ageing population, the increase in older people is also due to medical advances. For example, new treatments for diseases like lung and breast cancer have recently improved the life chances for some sufferers.
In 2020, the number of people living to 100 years or above in the UK increased by nearly one-fifth compared with 2019. This increase was driven by birth patterns in the early 1900s. The birth rate of the UK increased significantly between 1919 and 1920 because of the post-war baby boom at the end of World War One.